The old guard of the city’s educational establishment — the people who turned New York’s schools into places for everything but learning — won a big one yesterday.

The biggest losers are the kids themselves — and the city at large.

A so-called “rubber stamp” panel, appointed by state Education Commissioner David Steiner to evaluate Chancellor-designate Cathleen Black, voted to deny her the imprimatur she needs to take charge of the school system.

The vote wasn’t close — four against; two for; two “not yet” — and while Steiner isn’t bound by it, he’s certainly in sync with it.

He says he’ll deep-six the nomination unless Mayor Bloomberg agrees to appoint an independent deputy chancellor for academics — a person who has the education “credentials” Black lacks.

That’s absurd on the face of it.

The Department of Education is already top-heavy with folks possessing paperwork bound to make the education establishment giddy with joy.

If this were about qualifications, of course.

But it’s not.

Rather, it is about the teachers’ union and other special interests attempting to take back from Bloomberg what they see as their school system.

And, again, to hell with the kids.

Which is why it’s no coincidence that the United Federation of Teachers has been leading the charge against Black.

But mayoral control — which the Legislature in Albany approved after a pitched battle — means mayoral control.

And not David Steiner control — with all due respect to the commissioner.

Yes, a new poll shows New Yorkers believe the schools chancellor should be a career educator.

But, as Mayor Bloomberg rightly noted yesterday, this is not a popularity contest.

And, if chancellors were to be picked by public-opinion polls, Joel Klein would never have gotten the job — to the system’s considerable detriment.

Again, Steiner isn’t bound by the panel’s vote.

Which is a good thing — because his chief responsibility is to do what’s best for the schools.

And that means granting a waiver that will allow Black to become chancellor.